The Lambda LDS-W-28 is a 28V linear power supply engineered for precision analog circuits, medical equipment, and test instrumentation. Part of TDK-Lambda’s LD Series, it delivers exceptionally low output ripple and noise with convection cooling and automatic protection. The unit operates across dual input ranges—105-127 VAC or 210-254 VAC via transformer tap selection—across 47-440 Hz. Output voltage is adjustable to 28V ±5%, with current ratings of 4.0A @ 40°C, 3.4A @ 50°C, and 2.6A @ 60°C ambient temperatures, yielding a maximum output power of 116 W. The supply achieves 150 µV RMS ripple and 1 mV peak-to-peak noise, meeting MIL-I-6181D EMI standards with both conducted and radiated suppression.
Technical Specifications
• Output voltage: 28V ±5% adjustable
• Output current: 4.0A @ 40°C; 3.4A @ 50°C; 2.6A @ 60°C
• Maximum power: 116 W
• Input: 105-127 VAC or 210-254 VAC (selectable), 47-440 Hz
• Output ripple: 150 µV RMS; 1 mV peak-to-peak
• Line regulation: 0.005% + 0.5 mV (105-127 VAC)
• Load regulation: 0.005% + 0.5 mV (0 to full load)
• Temperature coefficient: 0.01% + 10 µV/°C
• DC isolation: Minimum 10 MΩ to ground at 750 VDC
• Transformer isolation: 4000 VAC input/output (MIL-T-27C Grade 6, electrostatic shield)
– Key Features
• Convection cooled—no forced air or external heat sinking required
• Automatic electronic current limiting
• Thermostat-based thermal overload protection with automatic reset
• Remote sensing capability to eliminate lead resistance effects
• Internal programming potentiometer (1-100% of Vo max)
• Fungus-proofed construction; no nutrient material used
• Three mounting surfaces with three mounting positions
• Meets MIL-T-27C transformer specification and MIL-I-6181D EMI compliance
– Environmental & Reliability
• Operating temperature: 0°C to +60°C (derating required above +40°C)
• Storage temperature: -55°C to +85°C
• Humidity: Method 507.1 (Procedures I & II)
• Vibration: Method 514.2 (Procedures X & XI)
• Shock: Method 516.2 (Procedures I & III)
– Typical Applications
Sensitive analog instrumentation, medical device power delivery, laboratory test equipment, and precision measurement systems requiring stable, low-noise DC output.
